Ballistic vests have saved the lives of many law enforcement officers in recent years. As a result, many law enforcement agencies have made it mandatory for their officers to wear ballistic vests while on duty.
Ballistic vests have been available in recent years as a protective panel having overlying layers of a fabric made from woven high tensile strength ballistic resistant polymeric fibers. Woven fabrics made from an aramid fiber known as KEVLAR, for example, have been used successfully in ballistic vests because of the high energy absorption properties of the fabric material. The material is also reasonably light in weight and flexible, which provides improved comfort when compared with previous vests which are made of nylon and metal and were therefore heavier and more rigid.
The comfort of a ballistic vest is extremely important, especially to law enforcement officers, because of the heat build-up that occurs from wearing a heavy and inflexible vest for the long hours an officer is on duty. Resistance to projectile penetration is a principal factor in designing a ballistic vest; and added protective layers can offer great protection against projectiles having higher threat levels, but added protective layers also add undesired weight and inflexibility of the vest.
In addition to woven KEVLAR fabric layers, ballistic vests have been made from other high performance synthetic fibers and composites to reduce weight and improve flexibility. However, ballistic vests using the lighter, more flexible ballistic materials also must offer the required minimal levels of protection against penetration by different types of projectiles.
Ballistic vests are regularly certified by ballistics testing to measure their ability to protect against different projectiles fired from different types of weapons at various angles. One ballistic test commonly used in the industry is the National Institute of Justice (NIJ) Standards 0101.03 which, in general terms, is a high performance standard requiring that the ballistic vest prevent penetration of specified rounds fired at velocities up to 1450 ft/sec. In addition to preventing such projectile penetration, "backface deformation" also is a required test factor in the NIJ Standard 0101.03 certification test. Backface deformation indirectly measures the trauma level experienced by a user from a projectile that does not penetrate the test panel. According to this test, the maximum allowable backface signature (bfs) containment for soft body armor requires a maximum allowable bfs of all rounds.
There is a need to provide a ballistic vest that is reasonably thin and light in weight as compared to vests previously made, is highly flexible and comfortable, and is also capable of meeting the NIJ high performance projectile test specifications. Providing such a vest at a reasonably low cost for the comparable high performance level is also a desired objective.
At the present time most ballistic vests worn by law enforcement officers are designed to meet Threat Level IIIA, IIA, or II Standards. One objective is to produce a reasonably lightweight and flexible vest that can meet the rigorous requirements of Level IIIA certification testing. There are other instances where lighter weight vests are more desirable even though they may not meet the Threat Level IIIA Standards. Here the challenge is to produce a lightweight vest capable of meeting the certification standards of NIJ Threat Levels II and IIA. An extremely lightweight vest with an areal weight less than 1.25 pounds per square foot and, more preferably, less than one pound per square foot that meets Level II and IIA standards is particularly desirable.